Back to the Future (or Worm
Holes)
Unlike the popular movie starring Michael J. Fox, time travel if it is possible with black holes, will not require the use of a DeLorean (ah shucks). The term Worm Hole has been given to the possibility of time travel through black holes. Basically a wormhole is a black hole that has an opening (a mouth) at its other end. To visualize this concept, imagine space being a long plastic sheet that has a hole in it, which is the one end of the wormhole or a black hole. If one were to travel to somewhere else in space, they would have to travel along the plastic sheet. However if there was a wormhole nearby, a person could go in this wormhole and arrive at their destination instantaneously. The wormhole is connecting the two points in space, no matter how far apart they are, as if they were right next to each other. Using the piece of plastic above, it would be as if the plastic was folded back on itself.
Scientists are not sure if wormholes exist and if it would be safe to travel in. One problem would be how to keep the tunnel open. The only way suggested by Kip Thorne is to use an ‘exotic’ material known as antigravity. Antigravity would force the tunnel walls apart and keep the wormhole open for travel.
Another concern is the twin or grandmother paradoxes. If someone were to travel in a wormhole, they could leave earth and return later. Since they are traveling in a black hole, their acceleration is different from earth’s therefore their twin left on earth would be older then they are upon their return. Or if a person traveled through a wormhole back in time, they could kill their grandmother. But if that happened, how would they exist. This leads scientist to believe that time travel is not possible.